SUMMARY Basic Science Core II (BSCII) focuses on in vivo and translational aspects of basic neuroscience and encompasses animal models and their behavioral testing, histology, microscopy, neuropathology, and neuronal functional studies. The BSCII assists investigators with animal models and behavioral testing allowing them to overcome the challenges of developing and characterizing new rodent models, particularly with behavioral phenotypes, which may be outside their areas of expertise. The core offers several models of neuroAIDS, including immunodeficient mouse models of HIV encephalopathy, in vivo HIV-1 infection using humanized mice, transgenic models including the HIV Tg26 transgenic mouse and the GFAP-Tat Tet-inducible transgenic mouse, inducible and tissue specific transgenic, knockdown, or knockout models, cell transplantation models, viral vector delivery, etc. Expertise in behavioral testing for cognitive changes in learning and memory, as well as peripheral neuropathies are provided. Expertise in the core includes experience in breeding and phenotyping of neurological models, and neurobehavioral testing which can be particularly challenging for investigators without prior experience. Assistance is also provided with histological and immunohistochemical evaluation of human autopsy and biopsy clinical samples from patients with neurological disorders, including AIDs, PML, neurodegenerative diseases, and CNS neoplasia, tissues harvested from experimental animal models, cell cultures and access to neuropathological consultation. The core provides study design and data interpretation, and microscopy services, including Laser Capture Microdissection (LCM) accessioning of tissue samples and nucleic acid extraction for downstream molecular biological applications, quantitative microscopy and imaging, and data analysis. We also offer state-of-the-art microelectrode array (MEA) studies for neuronal function in cell culture and whole animal systems. A key component of the core is to provide the necessary training to the investigators and their staff to gain the proficiency needed to independently conduct any of the routine core functions. These services assist investigators in the neuroAIDS community with an array of histopathological and in vivo translational resources.